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| Registros recuperados: 63 | |
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| Bonhommeau, Sylvain; Blanke, Bruno; Treguier, Anne-marie; Grima, Nicolas; Rivot, Etienne; Vermard, Youen; Greiner, Eric; Le Pape, Olivier. |
| The migration duration of European eel (Anguilla anguilla) larvae (leptocephali) from the spawning areas in the Sargasso Sea to the European continental shelf remains highly controversial, with estimates varying from 6 months to more than 2 yr. We estimated the fastest migration period and the shortest distance travelled by eel larvae by simulating Lagrangian particles released in the Sargasso Sea and by simulating a range of larval behaviours (fixed-depth drift, vertical diurnal migration and active-depth selection to maximize current velocity). This enabled us to compute (i) a passive drift speed, and (ii) a hypothetic swimming speed needed for European eel larvae to cross the Atlantic in 6 months (i.e., the migration duration estimated from otolith... |
| Tipo: Text |
Palavras-chave: Sargasso Sea; Migration duration; Leptocephali; Lagrangian modelling; Gulf Stream; Fractals; Anguilla. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6865.pdf |
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| Nikolic, Natacha; Montes, Iratxe; Lalire, Maxime; Puech, Alexis; Bodin, Nathalie; Arnaud-haond, Sophie; Kerwath, Sven; Corse, Emmanuel; Gaspar, Philippe; Hollanda, Stéphanie; Bourjea, Jerome; West, Wendy; Bonhommeau, Sylvain. |
| Albacore tuna (Thunnus alalunga) is an important target of tuna fisheries in the Atlantic and Indian Oceans. The commercial catch of albacore is the highest globally among all temperate tuna species, contributing around 6% in weight to global tuna catches over the last decade. The accurate assessment and management of this heavily exploited resource requires a robust understanding of the species’ biology and of the pattern of connectivity among oceanic regions, yet Indian Ocean albacore population dynamics remain poorly understood and its level of connectivity with the Atlantic Ocean population is uncertain. We analysed morphometrics and genetics of albacore (n = 1,874) in the southwest Indian (SWIO) and southeast Atlantic (SEAO) Oceans to investigate the... |
| Tipo: Text |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00653/76483/77555.pdf |
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| Bonhommeau, Sylvain; Le Pape, O.; Gascuel, D.; Blanke, Bruno; Treguier, Anne-marie; Grima, Nicolas; Vermard, Youen; Castonguay, M.; Rivot, E.. |
| Using Lagrangian simulations, based on circulation models over three different hydroclimatic periods in the last 45 years in the North Atlantic Ocean, the trans-Atlantic migration of the European eel Anguilla anguilla leptocephali was simulated via the passive drift of particles released in the spawning area. Three different behaviours were modelled: drifting at fixed depth, undergoing a vertical migration or choosing the fastest currents. Simulations included mortality hypotheses to estimate a realistic mean migration duration and relative survival of A. anguilla larvae. The mean migration duration was estimated as 21 months and the mortality rate as 3 center dot 8 per year, i.e. < 0 center dot 2% of A. anguilla larvae may typically survive the... |
| Tipo: Text |
Palavras-chave: Migration duration; Leptocephalus mortality; Lagrangian modelling. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6614.pdf |
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| Imzilen, Taha; Bonhommeau, Sylvain; Rouyer, Tristan; Kell, Laurence T; Chassot, Emmanuel; Barde, Julien. |
| In this note, we present an approach which has been recently used to execute online the set of codes used for eastern blue_n tuna (BFT-E) stock assessment at ICCAT. We aim at discussing the possible interest of the approach to the IOTC Community for focusing on Indian ocean tuna and tuna-like stocks and running other assesment models such as Stock Synthesis 3 (SS3). In 2014, ICCAT BFT-E working group has been able to execute thousands of model runs by using parallelization of R and Fortran codes on a supercomputer. This approach has a lot of scienti_c bene_ts, in particular for better including the multiple sources of uncertainty in assessment results and associated scienti_c advice. However, very few participants would be able to reproduce it without... |
| Tipo: Text |
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| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00360/47135/47084.pdf |
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| Chassot, Emmanuel; Bonhommeau, Sylvain; Dulvy, Nicholas K.; Melin, Frederic; Watson, Reg; Gascuel, Didier; Le Pape, Olivier. |
| Primary production must constrain the amount of fish and invertebrates available to expanding fisheries; however the degree of limitation has only been demonstrated at regional scales to date. Here we show that phytoplanktonic primary production, estimated from an ocean-colour satellite (SeaWiFS), is related to global fisheries catches at the scale of Large Marine Ecosystems, while accounting for temperature and ecological factors such as ecosystem size and type, species richness, animal body size, and the degree and nature of fisheries exploitation. Indeed we show that global fisheries catches since 1950 have been increasingly constrained by the amount of primary production. The primary production appropriated by current global fisheries is 17-112% higher... |
| Tipo: Text |
Palavras-chave: Bottom-up; Large Marine Ecosystem; Quantile regression; Sustainable fishing. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00002/11294/7836.pdf |
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| David-grignot, Stephane; Lamlih, Achraf; Belhaj, Mohamed Moez; Kerzerho, Vincent; Azais, Florence; Soulier, Fabien; Freitas, Philippe; Rouyer, Tristan; Bonhommeau, Sylvain; Bernard, Serge. |
| In the context of biosensor as much as Built-In-Self Test (BIST), on-chip sine-wave signal generation is a recurring research topic. Considering the implementation constraints, it implies a trade-off between the amount of resources and the signal quality. An attractive solution consists in combining several digital signals to build this analog sine-wave. The objective of this paper is to give an analytic study of various potential digital-based solutions. Thanks to this study, we prove that the technique consisting in setting the phase shifts and various amplitude values of the square-wave signals is the most efficient approach. This study allows the selection of the optimal square-wave signal parameters to cancel low-order harmonics of the generated... |
| Tipo: Text |
Palavras-chave: Harmonic cancelation; Sine-wave generation; On-chip signal generation. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00425/53678/54609.pdf |
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| Miller, Michael J.; Marohn, Lasse; Wysujack, Klaus; Bonhommeau, Sylvain; Kuroki, Mari; Freese, Marko; Pohlmann, Jan-dag; Watanabe, Shun; Blancke, Tina; Weist, Peggy; Castonguay, Martin; Westerberg, Håkan; Tsukamoto, Katsumi; Hanel, Reinhold. |
| Leptocephali of the shallow-water congrid eel Ariosoma balearicum are abundant during February–April in the Sargasso Sea, and larval and adult meristic data indicates this species includes several regional subpopulations/cryptic species. Four multiple-transect larval surveys (2011, 2014, 2015, 2017) were used to examine the geographic size distribution of two myomere-count types of A. balearicum leptocephali. High-count (HC) larvae were consistently mostly between 80 and 100 mm in size (60–132 mm; 87.9 ± 6.8 mm) as observed previously, and frequently had narrow size ranges. The usually larger LC larvae (78–176 mm; 111.4 ± 26.7 mm) were more abundant in western or central areas. HC larvae tended to decrease in size from west to east and increase from south... |
| Tipo: Text |
Palavras-chave: Ariosoma balearicum; Leptocephali; Larval dispersal; Sargasso Sea; Subtropical gyre; Cryptic species. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00509/62028/66491.pdf |
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| Bonhommeau, Sylvain; Dubroca, Laurent; Le Pape, Olivier; Barde, Julien; Kaplan, David; Chassot, Emmanuel; Nieblas, Anne-elise. |
| Trophic levels are critical for synthesizing species' diets, depicting energy pathways, understanding food web dynamics and ecosystem functioning, and monitoring ecosystem health. Specifically, trophic levels describe the position of species in a food web, from primary producers to apex predators (range, 1-5). Small differences in trophic level can reflect large differences in diet. Although trophic levels are among the most basic information collected for animals in ecosystems, a human trophic level (HTL) has never been defined. Here, we find a global HTL of 2.21, i.e., the trophic level of anchoveta. This value has increased with time, consistent with the global trend toward diets higher in meat. National HTLs ranging between 2.04 and 2.57 reflect a... |
| Tipo: Text |
Palavras-chave: Human ecology; Nutrition transition; Trophic ecology. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00171/28190/26609.pdf |
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| Bauer, Robert; Bonhommeau, Sylvain; Brisset, Blandine; Fromentin, Jean-marc. |
| Conservation and management measures for exploited fish species rely on our ability to monitor variations in population abundance. In the case of the eastern stock of Atlantic bluefin tuna (ABFT), recent changes in management policies have strongly affected the reliability of fishery-dependent indicators due to drastic changes in fishing season/area, fisheries selectivity and strategy. However, fishery-independent indices of abundance are rare for large pelagic fish, and obtaining them is often costly and labor intensive. Here, we show that scientific aerial surveys are an appropriate tool for monitoring juvenile bluefin tuna abundance in the Mediterranean. We present an abundance index based on 62 aerial surveys conducted since 2000, using 2 statistical... |
| Tipo: Text |
Palavras-chave: Thunnus thynnus; Index of abundance; Fishery-independent; Gulf of Lions; Mediterranean Sea; Strip transect; Distance sampling. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00281/39192/45096.pdf |
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| Bauer, Robert Klaus; Fromentin, Jean-marc; Demarcq, Herve; Bonhommeau, Sylvain. |
| We investigated the habitat utilization, vertical and horizontal behaviour of Atlantic bluefin tuna Thunnus thynnus (ABFT) in relation to oceanographic conditions in the northwestern Mediterranean Sea, based on 36 pop-up archival tags and different environmental data sets. Tags were deployed on early mature ABFT (127–255 cm) between July and November in 2007-2014, on the shelf area off Marseille, France. The data obtained from these tags provided 1643 daily summaries of ABFT vertical behaviour over 8 years of tag deployment. Based on a hierarchical clustering of this data, we could identify four principle daily vertical behaviour types, representing surface (≦10m) and subsurface (10–100 m) orientation, moderate (50–200 m) and deep (≧200m) diving behaviour.... |
| Tipo: Text |
Palavras-chave: Thunnus thynnus; Habitat use; Spike dives; Fronts; Thermal stratification; Archival tags. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00382/49329/49709.pdf |
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| Cury, Philippe; Boyd, Ian L.; Bonhommeau, Sylvain; Anker-nilssen, Tycho; Crawford, Robert J. M.; Furness, Robert W.; Mills, James A.; Murphy, Eugene J.; Oesterblom, Henrik; Paleczny, Michelle; Piatt, John F.; Roux, Jean-paul; Shannon, Lynne; Sydeman, William J.. |
| Determining the form of key predator-prey relationships is critical for understanding marine ecosystem dynamics. Using a comprehensive global database, we quantified the effect of fluctuations in food abundance on seabird breeding success. We identified a threshold in prey (fish and krill, termed "forage fish") abundance below which seabirds experience consistently reduced and more variable productivity. This response was common to all seven ecosystems and 14 bird species examined within the Atlantic, Pacific, and Southern Oceans. The threshold approximated one-third of the maximum prey biomass observed in long-term studies. This provides an indicator of the minimal forage fish biomass needed to sustain seabird productivity over the long term. |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00056/16770/14307.pdf |
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| Murad, Nour Mohammad; Guegan, Loic; Bonhommeau, Sylvain. |
| This article shows the effects of various parameters like modulation or the radio channel conditions on sea turtles trajectory estimated by terrestrial localization algorithms. This work is part of wireless sensors networks domain in the marine and terrestrial environment in the world of living beings. It allows to identify and understand the parameters that lead to inaccuracies over the sea turtles trajectory. Another important part of this project is to have a better understand about the morphology of the sea turtles and his environment. It also proposes another way to localize sea turtles. |
| Tipo: Text |
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| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00433/54487/55851.pdf |
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| Aoki, Yoshinori; Jusup, Marko; Nieblas, Anne-elise; Bonhommeau, Sylvain; Kiyofuji, Hidetada; Kitagawa, Takashi. |
| Formal approaches to physiological energetics, such as the Dynamic Energy Budget (DEB) theory, enable interspecies comparisons by uniformly describing how individuals of different species acquire and utilise energy. We used the DEB theory to infer the energy budgets of three commercial tuna species (skipjack, Pacific bluefin, and Atlantic bluefin) throughout all stages of ontogenetic development—from an egg to an adult individual and its eggs. Energy budgets were inferred from exhaustive datasets fed into a DEB-based mathematical model tailored for tuna fish until reaching a high goodness of fit and thus reliable estimates of the model parameters. The life histories of all three species are strongly influenced by morphological and physiological adaptations... |
| Tipo: Text |
Palavras-chave: Accelerated ontogeny; Bluefin tuna; Dynamic Energy Budget theory; Ecology and evolution; Energy speculators; Skipjack tuna. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00600/71238/69605.pdf |
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| Registros recuperados: 63 | |
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